From U.S. Pat. No. 5,120,265(A), a method and a shrimp peeling machine are known where skewed parallel rollers are used for peeling or shelling boiled shrimp.
The skewed rollers are characterized in that their longitudinal direction runs in the same direction as the shrimp peeling process direction.
It has been found, however, that there are some drawbacks of this known technique, including that the efficiency of the shrimp peeling machine from U.S. Pat. No. 5,120,265 to an extensive degree is dependent on the angle, by which the parallel rollers are skewed.
This drawback, among others, results in that it has not been possible to use the known technique in shrimp trawlers since the trawlers' movement in the open sea will inevitably change the angle in relation to a horizontal level by which the parallel rollers are skewed.
The hitherto known technique has therefore in practice only functioned satisfyingly on land based production facilities.
It is obviously a drawback since the shrimps therefore must be frozen on the trawlers and then thawed when they must subsequently be peeled on the land-based shrimp peeling facilities.
The peeled shrimps can subsequently be refreezed for sale to the consumers.
The finished product has therefore gone through two freezing processes before it can be sold to the consumers.
The quality of the finished peeled shrimps is therefore lower than if the shrimps could be finish processed including being peeled directly after they were landed on the shrimp trawlers.
Concurrently, the whole manufacturing process is allocated to two places namely partly on the fishing boats and partly on the land based shrimp peeling production facilities, which is not optimum.
From U.S. Pat. No. 2,832,092, there is known a shrimp peeling machine where the shrimp peeling occurs in a shrimp peeling process direction. The shrimp peeling machine includes an endless conveyor belt, which includes an endless chain with a number of joints, which contain cylindrical rollers.
The longitudinal axis of the cylindrical rollers is displaced 90 degrees in relation to the shrimp peeling process direction and the rollers are turned by activation of a toothed wheel. The endless conveyor belt is operated by two larger driving toothed wheels, since the conveyor belt's rotation is started by mesh between the toothed wheel on the shaft for the rollers and the larger driving toothed wheels, whereby the rollers are rotated in tracks, which run along the sides of the endless conveyor belt. The rollers include rollers with a polymeric surface and rollers from metal, where the rollers with the polymeric surface have a larger diameter than the rollers from metal. Shrimps are added to the endless conveyor belt in the top via a conveyance belt, the shrimps are shelled, by friction between the activated rollers and the released shells, and are collected under the chain.
It has been found, however, that the technique described in U.S. Pat. No. 2,832,092(A) does not function in a sufficiently efficient manner, including that it is not possible to adjust the mutual position between the rollers, which is used for shelling the shrimps.